The most amazing thing about the Loretta Lynch story is that the congressional community no longer views it as amazing.

Lynch is on course to be confirmed this month after the longest wait ever for a nominee to be attorney general — and very likely by the closest vote ever to put a new person in charge of the Justice Department. When Majority Leader Mitch McConnell announced Tuesday that the Senate debate on the nomination would begin next week, it marked 17 weeks and three days since President Barack Obama announced his choice for one of the most prestigious and pivotal positions in his Cabinet. At the time, Lynch was assured the bare minimum level of public support required for victory. Only four Republicans have announced they’ll join the 46 members of the Democratic Caucus in voting for her, meaning that at least for the time being Vice President Joseph R. Biden Jr. had best keep his March travel schedule a bit flexible.

Still, her sluggishly contentious path toward becoming the nation’s top law enforcement official has garnered relatively little public attention. That’s in large part because Lynch hasn’t become a focus of the daily partisan histrionics on the Hill or on cable news. And a big reason for that is because neither side views the fundamental dispute over her — extraordinary as it is by historical standards — to be remarkable at all in the context of today.

As the top federal prosecutor in Brooklyn, Lynch has earned just the sort of tough but fair reputation that’s customarily made for bipartisan smooth sailing in the Senate. But at least three-quarters of Republicans are going to oppose her anyway, mostly because of a single position she’s taken as the nominee: Obama was on solid legal ground in deferring deportations of as many as 5 million undocumented immigrants.

For essentially the first two centuries under our Constitution, senators afforded the president free rein to stock his Cabinet as he chose, except in the most extraordinary circumstances. Getting over the “advice and consent” hurdle was about proving competence for public service, demonstrating good manners and keeping your moral nose clean.

It would not have been newsworthy at all — let alone a rationale for disqualification — for an attorney general nominee to take the same position as the president who nominated her in a balance of powers battle with Congress. (In fact, it would have been much more problematic for a nominee to openly break with the president in such a dispute.)

And yet in the past three decades, a new standard has been taking hold so firmly it’s no longer generating much notice. At least once every presidential term, the party out of the White House campaigns to bury at least one nominee for a senior executive branch post — almost entirely by complaining about their differing ideologies. (At the start of George W. Bush’s presidency, the conservative John Ashcroft survived one such experience at the hands of the Democrats by winning confirmation despite 42 “no” votes, the record for opposition to a successful attorney general nominee.)

This time, there’s been an important additional twist: The single biggest reason Republicans oppose Lynch is that she disagrees with them on a single matter of public policy. They say her sticking up for the president’s immigration executive orders reveals one of two larger problems: that she won’t steer Justice in some fundamentally new and centrist direction (as if that was ever going to happen) and she can’t be counted on for the independence an attorney general sometimes needs to pursue the rule of law over the pull of politics.

Three GOP senators rejected these arguments and supported her in the Judiciary Committee: Orrin G. Hatch of Utah, Lindsey Graham of South Carolina and Jeff Flake of Arizona. So far her only other declared Republican backer is Susan Collins of Maine, who voted the way Obama wanted more than any other member of her caucus last year — 74 percent of the time, according to CQ Roll Call’s most recent annual votes studies. (All those details will be available for subscribers Friday on CQ.com .)

For a sense of where other support for Lynch might come from, several lists of Republican senators are worth reviewing.

Seven of them did not sign the open letter to Iran’s leadership warning against striking a nuclear agreement with Obama. They are a group that might fairly be described as the senators most inclined to stand by their chamber’s historic customs, which include not only staying out of the middle of diplomatic negotiations but also giving the president broad leeway on Cabinet nominees. Lynch backers Flake and Collins were joined in keeping their signatures off that letter by Tennessee’s Bob Corker and Lamar Alexander, Alaska’s Lisa Murkowski, Indiana’s Dan Coats and Mississippi’s Thad Cochran.

Led by Collins, all seven also sided with Obama more than 60 percent of the time on the Senate floor in 2014, when a new post-filibuster world gave the president the vast majority of his victories.

Alexander, Corker and Johnny Isakson of Georgia (64 percent presidential support last year) also voted six years ago to confirm Eric H. Holder Jr. as attorney general. (The other five Republicans who voted for Holder and are still in office are Hatch, Graham, Collins, John McCain of Arizona and Charles E. Grassley of Iowa.)

Grassley opposed Lynch in Judiciary despite some speculation he’d vote “yes,” in part because he’s hoping to win a seventh term in 2016 in a state Obama carried twice.

That leaves three other senators who are up for-re-election next year in states the president won in both 2008 and 2012. They happen to have backed Obama on at least 5 out of 8 roll call votes last year: Kelly Ayotte of New Hampshire, Mark S. Kirk of Illinois and Rob Portman of Ohio.

Consider the aggregate rosters of Iran letter non-signers, above-average Obama backers, Holder voters and incumbents running in blue states. Those lists yield a universe of nine potential GOP supporters beyond the four already committed. Securing all 13, plus the 46 Democrats, would give Lynch 59 votes — not even sufficient to break an old-fashioned filibuster, and only one more than the 14-year-old record for minimal support for an attorney general.